The invention relates to a rotating machine part with a base or housing which rotates in a heat transmitting medium, particularly a cycloid propeller, and more particularly relates to heat transmission within the housing of the machine part. In the case of such a machine part. The example the wheel body of the cycloid propeller for example, oil which lubricates and cools the bearing points and the transmission circulates in the interior, from which the heat is emitted to the outside via the outer wall of the machine part to the medium. The oil should circulate in the interior in a suitable manner for this purpose. At the same time, the heat transmission surfaces of the machine part are in general located radially on the outside.
The object of the invention is significantly to improve the heat transmission with respect to the bearing point and cooling of the machine part.